1. Field of the Invention
The present invention relates to a modulation/demodulation technique.
2. Description of the Related Art
Methods for converting a data signal to be transmitted into a pulse train can be roughly classified into techniques whereby information is carried on the amplitude of a signal, and techniques whereby the information is carried along the time axis of the signal. Known examples of the latter techniques include pulse position modulation (PPM), pulse width modulation (PWM), frequency modulation (FM), PFM (pulse frequency modulation), pulse interval modulation (PIM), etc. For example, PPM is employed in communication using optical fibers or infrared remote controllers, etc. PWM is employed in switching power supplies, the power control operation for single-bit digital audio amplifiers, etc.
In the wireless communication field, examples of the methods for transmitting data using a phase shift of the sinusoidal carrier wave, instead of the pulse thereof, include PSK (Phase Shift Keying), DPSK (Differential Phase Shift Keying), GMSK (Gaussian Filtered Minimum Shift Keying), QAM (Quadrature Amplitude Modulation), OFDM (Orthogonal Frequency Division Multiplexing), etc.
Through an ideal transmission line of tens of cm on a printed circuit board, conventional architectures provide a transmission rate of around 20 Gbps.
In recent years, there has come to be an increase in the amount of data to be transmitted, and such data has come to be transmitted at a higher speed. This leads to a demand for implementing techniques for transmitting data at even higher bit rates.